Figure 8.

Langendorff experiments in mouse heart. A, Representative atrial electrogram traces showing effect of burst pacing (100 Hz) in the absence (control, left) and presence (right) of blebbistatin (5 µmol/L) (2 mmol/L K⁺ in both). B, Grouped bar chart showing mean±SEM inducibility of atrial arrhythmic activity for each potassium level, differentiated by the presence or absence of blebbistatin. The chart highlights significant main effects of blebbistatin, F(1, 72)=20.06, P<0.0001, and potassium, F(3, 72)=14.91, P<0.0001. C, Mean±SEM arrhythmic episode duration for each potassium level, in the presence or absence of blebbistatin. The graph highlights the significant effect of potassium, F(3, 36)=3.52, P<0.05. D, Kaplan-Meier plot showing the percentage of hearts without arrhythmic activity. *P<0.05, ***P<0.001 vs control. n=number of hearts. Comparison using 2-way ANOVA followed by a Fisher Least Significant Difference post hoc test (B and C) and the Gehan-Breslow-Wilcoxon test (D). Ctrl indicates control.